Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011881 (diabetic nephropathy)
 10,836 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Glomeruli from streptozotocin-diabetic and age-matched nondiabetic rats were quantitatively isolated by a differential sieving technique. The insoluble glomerular basement membranes were purified following sonic disruption in the presence of proteolytic inhibitors. The yield of glomeruli and of glomerular basement membrane relative to the amount of renal cortex and the body weight of the animals, as well as the calculated amount of basement membrane per glomerulus, were all significantly greater in diabetic rats when compared to non-diabetic controls. Glomerular basement membranes from normal and diabetic rats were solubilized by reduction and denaturation in the presence of SDS and subjected to agarose gel analysis. About 65% of both normal and diabetic basement membrane was solubilized by this procedure, and the elution profiles of non-diabetic and diabetic preparations were similar. These results suggest that rat renal basement membrane is qualitatively similar but quantitatively increased in streptozotocin-diabetes. Since glomerular enlargement and accumulation of basement membrane are characteristic of human diabetic nephropathy, the findings also suggest that the streptozotocin-diabetic rat is an appropriate animal model for studies relating to the pathogenesis of this complication of diabetes.
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PMID:Glomerulopathy in rats with streptozotocin diabetes. Accumulation of glomerular basement membrane analogous to human diabetic nephropathy. 15 28

To evaluate the importance of tubular proteinuria in diabetic nephropathy, we studied the serial changes of micro-albuminuria, microproteinuria and protein patterns by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) in 38 diabetic patients over 8 months. There was a significant correlation between the amount of micro-albuminuria measured by radio-immunoassay and the amount of microproteinuria quantitated by the Coomassie brilliant blue dye binding method (r = 0.976; p less than 0.0001). Micro-albuminuria of 50 mg/day was equivalent to microproteinuria of 190 mg/day. Among the 38 diabetic patients, 26 had micro-albuminuria above 50 mg/day, while 12 had micro-albuminuria below this level. There was a significant correlation between the amount of microproteinuria and haemoglobin A1, showing that the quantity of microproteinuria was affected by metabolic control. Diabetic patients with micro-albuminuria of above 50 mg/day have a significantly higher diastolic blood pressure than those below this level. Among the diabetic patients with micro-albuminuria of less than 50 mg/day, the amount of micro-albuminuria and microproteinuria remained constant, whereas progressive increases in micro-albuminuria and microproteinuria were observed among the 12 diabetic subjects with micro-albuminuria above 50 mg/day. These support the prognostic importance of this quantity of micro-albuminuria. The protein patterns as revealed by SDS-PAGE with Coomassie blue staining show a significant loss of low-molecular-weight proteins in 7 patients, which may therefore suggest tubular damage. The loss of tubular proteins persisted over a period of 8 months in all 7 subjects, and the amount gradually increased over this period.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Eight-month longitudinal study of urinary excretion of albumin and tubular proteins in diabetic subjects. 170 39

Urinary albumin fragments (uAF) from patients with NIDDM were analyzed as a possible factor in the early discovery of diabetic nephropathy before emergence of microalbuminuria. SDS-PAGE and immunoblot assay were employed for detection of uAF. Samples from 252 patients with NIDDM, 158 patients with non-diabetic diseases, and 48 healthy volunteers were examined; uAF were detected in 139 (55.2%), 94 (59.5%), only one (2.1%), respectively. In diabetic patients with normoalbuminuria, uAF were detected in 48 out of 159 cases (30.2%). Two years after the initial study, 3 of the 17 diabetic patients (17.6%) with normoalbuminuria and uAF showed micro- or macroalbuminuria. It was concluded that detection of uAF might be useful for the early detection of diabetic nephropathy in NIDDM.
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PMID:Urinary albumin fragments as a new clinical parameter for the early detection of diabetic nephropathy. 754 25

Microalbuminuria is considered to be an early indicator of diabetic nephropathy. In this report, we developed an enzyme-linked immunosorbent assay (ELISA) for the measurement of urinary albumin (UA) and examined UA in 38 patients with insulin-dependent diabetes mellitus (IDDM). The assay range of ELISA for albumin was 5-1,000 ng/ml, and the albumin levels determined by ELISA were well correlated with those by immunoagglutination methods. The UA values of daytime single-void specimens in control subjects, which correlated significantly with UA excretion rates (micrograms/minute) in 24-hour urine, were 10.9 +/- 8.2 micrograms/mg creatinine. In 38 IDDM patients, there were four cases with microalbuminuria and one case with overt nephropathy. Their disease duration was longer than 8 years, and the diabetic control was fair to poor. On SDS-PAGE analysis. the urinary protein of the cases with microalbuminuria consisted mainly of albumin, and in the case of nephropathy, an IgG band was also detected. The measurements of UA in single-void specimens by ELISA is a satisfactory approach to detect impending nephropathy in IDDM patients.
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PMID:An enzyme-linked immunosorbent assay for urinary albumin in patients with insulin-dependent diabetes mellitus. 768 36

Previous investigations have demonstrated that growing mesangial cells in high glucose concentration stimulates extracellular matrix synthesis and also increases the expression of TGF-beta. We tested whether the stimulation of extracellular matrix production is mediated by autocrine activation of TGF-beta, a known prosclerotic cytokine. Addition of neutralizing anti-TGF-beta antibody, but not normal rabbit IgG, significantly reduced the high glucose-stimulated incorporation of 3[H]proline. Denaturing SDS-PAGE revealed that mainly collagen types I and IV were stimulated by high (450 mg/dl) D-glucose. This high glucose-mediated increase in collagen synthesis was reduced by the anti-TGF-beta antibody. Treatment of mesangial cells grown in normal (100 mg/dl) D-glucose with 2 ng/ml recombinant TGF-beta 1 mimicked the effects of high glucose. Furthermore, the anti-TGF-beta antibody significantly reduced the increase in mRNA levels encoding alpha 2(I) and alpha 1(IV) collagens induced by high glucose. Thus, the high glucose-stimulated increase of collagen production in mesangial cells is mediated, at least in part, by autocrine TGF-beta activation. We postulate that the interception of the glomerular activity of TGF-beta may be an effective intervention in the management of diabetic nephropathy.
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PMID:Stimulation of collagen gene expression and protein synthesis in murine mesangial cells by high glucose is mediated by autocrine activation of transforming growth factor-beta. 811 92

We examined structural changes in bovine kidney tubular basement membrane (TBM) following in vitro nonenzymatic glycosylation (NEG). Isolated TBM was incubated for 2 wk at 37 degrees C in the absence of sugar or in the presence of either glucose or ribitol under conditions that minimized degradation and oxidative damage. NEG and crosslink formation in glycated TBM were confirmed by decreased solubility, increased amounts of low mobility material by SDS-PAGE, and increased specific fluorescence compared to controls. Morphological analysis using high resolution, low voltage scanning electron microscopy (LV-SEM) revealed a complex three-dimensional meshwork of interconnecting strands with intervening openings. Glycated TBM underwent distinct morphological changes, including a 58% increase in the amount of image surface area occupied by openings. This was due to an apparent increase in the number of large openings (diameters > 12.5 nm), whereas the number of small openings (diameters < 12.5 nm) remained unchanged. These findings corroborate earlier physiological studies, which established that the loss of glomerular permselectivity seen in patients with diabetic nephropathy is due to the formation of large pores in the kidney filtration barrier of which the BM is a major component. We conclude that NEG and crosslink formation among BM components lead to modifications of BM ultrastructure, which could play a role in loss of barrier function in diabetic microangiopathy and nephropathy.
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PMID:Nonenzymatic glycosylation-induced modifications of intact bovine kidney tubular basement membrane. 825 58

N-Acetyl-beta-D-glucosaminidase (NAG) can be found in kidney in high activity. By determination of this enzyme activity in urine nephropathies can be recognized reliably. We have measured this lysosomal enzyme in the urine (Colorimetric method by Noto) of 206 children suffering from diabetes mellitus to find out whether diabetic nephropathy can be detected as soon as possible. Additional beta 2-microglobulin (ELISA) was measured in urine, which is reabsorbed nearly complete in the tubulus. The several proteins in urine were identified by SDS-PAGE. A high excretion of beta-NAG was found in children and adolescents with a poor metabolic control (elevated HbA1c). There was no correlation between NAG activity, duration of the diabetes and the age of the children. An elevated excretion of beta-2-microglobuline could be found only in seven children with a duration of the diabetes about six years; their HbA1c levels were high. The SDS-PAGE showed a pattern of glomerular protein excretion according to the duration of the diabetes. However there was no significant correlation to the metabolic control. Only in four children we ascertained mixed proteinuria. The increasing levels of urinary NAG may represent the increasing severity of nephrotic damage by diabetes. The estimation of NAG levels in urine would seem to be reliable in the early detection of diabetic angiopathy also and may serve as an index of diabetic control independent of blood sugar levels.
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PMID:[N-acetyl-beta-glucosaminidase (beta-NAG) in urine: a parameter for early detection of diabetogenic nephropathy in childhood]. 836 78

The presence of excessive amounts of advanced glycation end products (AGE) in tissues or in the circulation may critically affect the progression of diabetic nephropathy. Circulating AGE levels, mainly in the form of small peptides, increase in diabetic patients or in patients with end-stage renal disease. This rise correlates with the severity of the nephropathy. However, so far little is known about the fate of AGE-proteins and AGE-peptides in renal tissue, and in order to elucidate this issue we undertook the present study. AGE-bovine serum albumin (AGE-BSA) and AGE-peptides were prepared, characterized by spectrophotometry, spectrofluorometry, chromatography and SDS-PAGE. AGE-peptides reacted in vitro with LDL producing biochemical and ultrastructural modifications. Using colloidal gold post-embedding immunoelectron microscopy with an anti-AGE antibody generated in our laboratory, we followed, in a short-term kinetic study, the cellular and sub-cellular localisation of circulating AGE-products throughout the nephron. AGE-peptides or AGE-BSA were injected into otherwise normal rats and detected by protein A-gold immuno-cytochemistry after 15, 30 or 45 min of circulation. Most of the AGE-BSA was found in the lumen of capillary vessels and distributed along the endothelial side of the glomerular basement membrane. Presence on mesangial matrix was also apparent. AGE-peptides were easily filtered and actively reabsorbed by the proximal convoluted tubule. At 15 min, little labelling was found in the glomerular wall. Instead, the labelling was present in the urinary space and microvilli of epithelial cells. Early endosomes displayed intense labelling as well. At 45 min, late endosomes and lysosomes added to the pattern of labelling. The distal tubule epithelial cells were devoid of labelling for any of the intervals studied. AGE-peptides but not AGE-BSA could be detected in the urine of injected rats. These observations point to participation of the endo-lysosomal apparatus of the proximal convoluted tubule to the disposal of AGE-peptides, while giving an ultrastructural support for a key role of the kidney in AGE catabolism.
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PMID:Renal fate of circulating advanced glycated end products (AGE): evidence for reabsorption and catabolism of AGE-peptides by renal proximal tubular cells. 863 66

Glycation of basement membrane collagen IV has been implicated as a major pathogenetic process leading to diabetic microvascular complications. To evaluate the relevance of carbohydrate-induced modifications on collagen IV in diabetic nephropathy, we isolated the cross-linking domains 7S and NC1 from the glomerular basement membrane (GBM) of patients with diabetes mellitus. Modifications characteristic for glycated proteins were identified when the domains from diabetic kidney were compared with the same domains from human placenta as an unmodified control. In both domains a marked formation of inter-and intramolecular cross links could be demonstrated by SDS-PAGE. Furthermore circular dichroism studies showed a decrease in helicity of the 7S domain from human diabetic kidneys of 13%, indicating denaturation already at room temperature. Thermal transition profiles, showing a shift of the denaturation temperature towards a lower temperature, with loss of a distinct second melting point, confirmed this observation. Our data provide further evidence for a possible role of protein-modification by glycoxidative reactions in the onset of diabetic nephropathy in vivo.
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PMID:Biochemical and biophysical alterations of the 7S and NC1 domain of collagen IV from human diabetic kidneys. 975 26

Pathological changes in the urine sodium dodecyl sulphate gel electrophoresis (SDS PAGE) patterns often precede the occurrence of any sign of renal involvement in diabetes. However, data concerning the most frequent SDS PAGE pattern of the urine in early stages of type I diabetes mellitus are controversial. In the present study an SDS PAGE technique has been used that provides an adequate sensitivity for the detection of the abnormal pattern. Urinary proteins have been analyzed by SDS PAGE in twenty two diabetic adolescents and twenty four age matched controls. Albumin concentration, and N acetyl-beta-D-glucosaminidase (NAG) activity were also measured in the same samples. There was no significant difference in urine albumin concentration and NAG activity between diabetic children and controls. However twelve patients showed an electrophoretic pattern characteristic for glomerulopathy, two had a pattern indicating tubular dysfunction and another two patients had a mixed pattern. Among the twenty four controls only three showed abnormal electrophoretic patterns. The results support the view that early stages of diabetic nephropathy may involve both glomerular and tubular dysfunction. However the exact clinical and prognostic significance of the information provided by SDS PAGE analysis remains to be elucidated.
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PMID:Electrophoretic analysis of urinary proteins in diabetic adolescents. 1143 99


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